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By A T. Job, P R. McAree

There is significant value at stake in the mining industry from the implementation of new technologies that support the enhanced profitability and sustainability of mines. However, in order to realise this value, new technology must be implemented in a way that is both effective and sustainable. The industry has a mixed history for technology implementation that provides fertile ground for understanding what is necessary for innovation to deliver value. This paper describes early stage research investigating why this is so, with the aim of improving how to deliver value. Several case studies are provided covering both successful and unsuccessful technology interventions. The paper identifies the common factors that emerge from the case studies, and offers a path forward for further research in this area.CITATION:Job, A T and McAree, P R, 2017. Three case studies on the implementation of new technology in the mining industry, in Proceedings Iron Ore 2017, pp 407–414 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By G Stanway, P Mahoney, C Griebel

The Mining Innovation – State of Play was initiated three years ago by VCI in partnership with the University of Western Australia. The ambition was to create a ‘think tank’ type platform to support industry discussion on how it is performing in terms of innovation at a strategic level, what needs to change in the industry ‘ecosystem’, and how businesses may more effectively develop their strategy and architecture to innovate for competitive advantage.The drivers for this ambition were straightforward. The industry recognises itself as being conservative with respect to innovation and it knows the business and community endowment dividend from getting better at innovation is large; however, much of the material that seeks to provide insight on innovation tends to be drawn from industries that do not have the same high capital, long life cycle and market uncertainty characteristics as that faced by mining. Material that does focus on mining innovation is orientated towards technical innovation, not innovation strategy. There exists a significant knowledge gap, and filling it is valuable to both mining businesses and communities.The 2014 Mining Innovation State of Play report (Stanway, Griebel and Mahoney, 2014), based on a survey of over 230 mining executives, uncovered a range of insights but left several questions unresolved. The people with the best perspective on these questions are CEOs. They can see the business issues with sufficient clarity and have the influence to shape both the industry and its organisations, as seen in Figure 1. Discussing these questions with the view to progressing our collective understanding was the primary reason this interview series was conducted.Unsurprisingly, interviewing 15 CEOs and Chairpersons from different industries and commodities, across the globe resulted in a broad range of views. The discussions were frank and often blunt in assessing the short comings in the industry and suggestions for improvement. This degree of candour is hugely valuable as a basis for improvement. In the end, four key areas emerged as a basis for improvement.CITATION:Stanway, G, Griebel, C and Mahoney, P, 2017. Mining Innovation State of PlayTM – iron ore insights, in Proceedings Iron Ore 2017, pp 439–442 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By M C. Goode

The use of electrical or electronic safety systems to protect personnel, and the engineering tasks associated with the design, manufacture and maintenance of these systems are referred to using the term ‘functional safety’. In the past ten years, the use of such systems has transitioned from its traditional base, in oil and gas major hazard facilities, to being a part of most large mining and materials handling projects. In particular, functional safety is rapidly becoming a significant component of Australian iron ore projects, typically in the form of emergency stops, remote isolation, drive through interlock, robot cell entry or mobile machine anti-collision systems. While these types of systems have been in use in iron ore for a long time, functional safety standards (eg AS61508, AS62061, AS4024.1503) require more rigourous demonstration of the level of risk reduction provided by the systems.The early engineering project development phases require a number of key decisions to be made around functional safety implementation. The decisions made at this point in a project will go on to dictate the required types of risk assessment and analysis, equipment selection, sizing of substations, and training and maintenance requirements for owners. For project teams that are unfamiliar with functional safety, or inexperienced in its application, an incorrect decision or failure to understand the requirements of the chosen standard can lead to a failure to meet contract requirements, as well as major cost and schedule overruns.This paper examines the implications of functional safety on early engineering studies, focusing on the following questions: How does a designer or company determine what standard is best suited to their project? What key aspects of functional safety design need to be considered during project development? And finally, how can the impact of functional safety to the project be minimised?CITATION:Goode, M C, 2017. Functional safety impacts on study stages of major projects, in Proceedings Iron Ore 2017, pp 347–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By G A. Wellwood

What do all iron ore mines have in common? Perfect production days! Yes, those harmonious 24-hour periods when the stars align and the daily output number rockets past the long-term average to hit new heights. While perfect days are always welcome, the focusing question iswas that just a ‘flash in the pan’ (due to a special cause) or an indication of the process’s capability (with clues to the common causes) which, if addressed, could make every day perfect? In the context of today’s operating environment, with the need to maximise productivity at minimum cost, it’s an important question.Investigations reveal that the throughput difference between a perfect production day and the average is often in the order of 40 per cent, and that bulk solids handling (BSH) system deficiencies are the largest (>50 per cent) class of lost opportunity. Root causes for underperformance of elements in BSH systems can often be traced back to the detailed design and even study-stage oversights. Essentially baked into the fabricated plant, operations are effectively forced to accept them at the point of practical completion and then deal with the consequences for the life of the mine. Subsequent normalisation of these defects in the planning process reduces visibility and hence the impetus for long-term solutions in favour of lower targets and quick fixes to keep the show on the road. On an industry wide basis the design processes and assumptions responsible for BSH system underperformance become enshrined as common practice and hence repeated across sites and organisations.In addition to making the case for action, practical steps that can be taken to help realise the significant productivity prize and avoid the problems in first place are provided.CITATION:Wellwood, G A, 2017. One perfect (production) day – a bulk solids handling perspective, in Proceedings Iron Ore 2017, pp 443–452 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By G Siboni, A Correa De Araujo, M Gotelip Barbosa, M J. Venturini

In support of the development of its Liberian iron ore project, ArcelorMittal Mining Research and Development (AM Mining R&D) has performed characterisation and beneficiation test work on drill core samples received from the proposed mine area. In addition to this, a sinter feed product was composed by blending and processing the drill cores in order to predict sintering performance of the ore. This article presents the methodology used to prepare the drill core blend for characterisation, as well as describe the sinter pot trial. The results are presented, demonstrating how important this type of study is for the development of an iron ore deposit.CITATION:Gotelip Barbosa, M, Siboni, G, Venturini, M J and Correa de Araujo, A, 2017. The use of drill core blends to predict sintering performance, in Proceedings Iron Ore 2017, pp 297–302 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By T Higuchi, L Lu

The quality of iron ore fines have been deteriorating, which has affected sinter quality and productivity adversely. New pretreatment and sintering technologies are therefore required to tackle the gradual change in the quality of iron ore fines. In the sintering process, iron ore fines are first granulated with fluxes such as limestone and coke breeze, and are then loaded and fired in a sinter machine. Sinter productivity and quality are heavily influenced by the reactions occurring in the sintering bed. Hence fundamental understanding of these high temperature properties of ores is urgently needed.Formation of initial sinter melt, penetration and assimilation of nucleus particles by the initial melt, and consolidation and final solidification of final sinter melt are believed to be the key sintering reactions. The assimilation and penetration phenomena have been studied separately in the literature with model particles and diffusion couples and are therefore difficult to relate to sinter quality. In addition, the effect of ore mineralogy has not been studied in detail.In this study, tablets consisting of coarse particles from various iron ore fines as nucleus particles and chemical reagents as adhering fines were made and fired under various sintering conditions to investigate the penetration and assimilation behaviour simultaneously. The degree of assimilation, pore structure, compressive strength of the resultant analogue sinters were evaluated and the relationship between sinter strength and ore characteristics was further discussed. The nucleus particles from Ores A and B were found to be more porous and assimilated more readily with sinter melt, resulting in a viscous melt and a macro-porous sinter structure. The nucleus particles from Ores C and D on the other hand, assimilated less readily with sinter melt, resulting in a fluid melt and a denser sinter structure. This is consistent with the results reported in the literature, suggesting that the present evaluation method can be utilised for studying sintering reactions and predicting sinter quality.CITATION:Higuchi, T and Lu, L, 2017. Evaluation of sintering behaviour based on ore characteristics, in Proceedings Iron Ore 2017, pp 303–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By D François-Bongarçon

After a review of the progresses made on the liberation factor theory since its inception by Gy (1982), a new and surprising result of great practical importance is presented: the liberation factor. First introduced simply as a number between 0 and 1, then shown to be the ratio of two variances, is now shown to be well approximated by the proportion of liberated mineral.CITATION:François-Bongarçon, D, 2017. Evolution of the concept of the liberation factor and a surprising new result, in Proceedings Eighth World Conference on Sampling and Blending , pp 307–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By C Paoletti

About 15 years ago the debate on the reliability of sampling procedures for agricultural food and feed commodities was initiated by a few brave scientists who questioned the representativeness of what, at the time, were routine sampling procedures established exclusively on the basis of tradition and practical feasibility. Over time several national and international organisations contributed to the discussion, developing standards and publishing papers either to underline the fact that sampling is always a source of error, in itself, which cannot be overlooked, or to minimise the relevance of sampling on the basis of argumentations linked to time and money limitations. The latter dominated, but is nevertheless impossible to accept from both a scientific and a responsible management perspective. Here the author presents an historical overview of these past 15 years, illustrating the most controversial issues, reporting major achievements in food/feed sampling, highlighting milestones, as well as unresolved problems that still need the attention and contribution from the sampling community. The need to incorporate Theory of Sampling (TOS) into food/feed safety assessment (pre-market), as well as into food/feed safety monitoring (post-market) has recently been highlighted, and the practical applicability of TOS to base food/feed safety decisions on representative sampling, has been explored and documented via concrete examples of risk analysis in different areas of food/feed industrial production chains. Now it is time to move forward and ensure that TOS is fully integrated into the well-established Food and Agriculture Organization (FAO) / World Health Organization (WHO) risk assessment approach, in order to guarantee a transparent and correct universal frame for risk assessment and the subsequent management decision-making process. WCSB8 offers the ideal platform to explore the best way to do so, switching from a theoretical discussion of correct sampling principles for food and feed agricultural commodities to practical recommendations in the interest of consumers, worldwide. These 15 years have also been a personal journey of interesting dimensions, indeed a veritable roller-coaster ride in-and-out of the scientific, technological, industrial and (last but not least) regulatory worlds. The start was WCSB2 in 2004, when I flew to Australia to discover if in other areas sampling had been identified as an unavoidable issue and, if so, what the solution was. There, I found a good travel companion who today is still on my side, to assemble the puzzle and explore how to shape the future, to concretely answer to the 15 years’ quest for proper sampling in the assessment and monitoring of food/feed safety.CITATION:Paoletti, C, 2017. Assessing and monitoring food and feed safety – a 15 year quest for proper sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 39–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By D François-Bongarçon

The link between geostatistics and Theory of Sampling (TOS) is examined again in view of new findings made while trying to compare predicted sampling variances and estimated grades (using geostatistics) on the same material, and this provides an important consistency requirement whenever calculations are made that involve both theories in a comparative way. It also briefly explores the relationship to De Wijs fractal model of mineralisation and eventually provides new support for the use of consistency theory for calibrating TOS variance formulas.CITATION:François-Bongarçon, D, 2017. Theory of Sampling and geostatistics – the ultimate link, in Proceedings Eighth World Conference on Sampling and Blending , pp 391–394 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By A Parbhakar-Fox, S C. Dominy

The prediction of acid and metalliferous drainage (AMD) from mine waste materials is critically important during all stages of the mine value chain. However, to determine such geoenvironmental characteristics static and kinetic testing of individual waste units must be performed on representative samples. The importance of sample selection cannot be underestimated; it is the single most critical aspect of any geoenvironmental investigation. Poor sampling techniques and inadequate sample selection will contribute to excessive variance, difficulties in interpretation and incorrect assessment. By undertaking mesotextural characterisation based on hyperspectral mineralogical data (with sulfur assay data if available), opportunities to improve sampling strategies are presented. Such data will inform the selection of samples for low-cost total sulfur, paste pH and geoenvironmental logging, which collectively will allow for accurate AMD forecasting and improved sampling practices to be achieved. Once sampled, robust quality assurance/quality control (QA/QC) protocols must be developed where the use of international certified reference standards become obligatory. This is currently not practised, resulting in inter-laboratory discrepancies when undertaking waste classification. Further improvements in geoenvironmental characterisation testing lies in the adoption of blended static testing protocols, whereby blends of waste materials can be efficiently tested so as to give an early forecast as to whether they will produce acidic or metal-laden drainage. Such information is integral in developing a waste schedule that will allow for a non-acid forming waste landform to be constructed right from the start of the operational phase. Ultimately, improvements in this discipline lie in technological innovations with regards to mineralogical characterisation, and by offering geoscience and minerals engineering students a competent education in the discipline. Collectively, this will empower a step-change in AMD prediction and waste handling, and will make the realisation of the United Nations Sustainable Development Goals a reality, rather than a dream.CITATION:Parbhakar-Fox, A and Dominy, S C, 2017. Sampling and blending in geoenvironmental campaigns – current practice and future opportunities, in Proceedings Eighth World Conference on Sampling and Blending , pp 45–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By D W. Wall, J P. Vagenas

Questions of sampling precision and accuracy affect every process plant in differing ways and to differing extents. To address these perceived issues, chemists, metallurgists and engineers are often asked to check their results to confirm their reliability. However, it is not possible to achieve the level of detail required to check every sample, especially if the event has already occurred. No operation has the resources to frequently sample every point in the process for the purpose of verification.One way to address this scenario is by generating a sufficiently detailed comparative data set from a dynamic mass balance simulation of the processing plant. This mass balance uses both sample and plant instrument data to model every flow, while also taking inventory changes and process chemistry into account.The mass balance data can be used to identify any bias present in plant sampling and analysis. It can also be used to verify any unexpected assay results by taking a holistic view of the process. Improving the precision and accuracy of sampling data helps support operational decision-?making and understanding. It also improves the accuracy of the dynamic mass balance used in this process, facilitating further improvements.CITATION:Vagenas, J P and Wall, D W, 2017. The benefits of automated metallurgical accounting for plant sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 203–210 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By O Bøckman, E Thisted, K H. Esbensen, U Thisted

Process industry measurement systems, once installed, are often interpreted as static black boxes delivering correct values as long as not proven otherwise. After first implementation and set-up with a distinct sampling frequency, they often run ‘forever’ without checking if this frequency is still appropriate with respect to changed raw materials characteristics, different process conditions or changed customer specifications. Failure detection is based on operator experience and skills (often close to an art form) and/or from control measurements of reference samples. This may well be too late for many industrial process contexts. An appropriate sampling frequency is a critical success factor for valid monitoring and control.Based on the methodology of variographic analysis we here illustrate how to design/re-design/optimise an industrial measurement system in terms of sampling frequency, discretisation and accuracy based on customer specifications. We also show how variographics can be used to monitor for deviations. We use experience from process industry to show how these methods can be used not only for product characterisation, but also for monitoring input factors, process indicators and measurement of these. The information hidden in the vast amounts of data that is continuously created in modern process industries can be utilised to cut costs in the measurement activities and at the same time contribute to early error detection. We illustrate by case examples from production processes at a nickel refinery, supporting the Lean and Six Sigma methodology. This will provide a standard operating procedure for monitoring the stability of measurement systems, and provide a basis with which to discuss how a variographic approach can be integrated with the Lean and Six Sigma approach as an online tool to map, characterise and validate measurement systems and thus avoid more cumbersome measurement system analysis in full detail.CITATION:Thisted, E, Thisted, U, Bøckman, O and Esbensen, K H, 2017. Variographic case study for designing, monitoring and optimising industrial measurement systems – the missing link in Lean and Six Sigma, in Proceedings Eighth World Conference on Sampling and Blending , pp 359–366 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By R J. Romañach

The theory of sampling (TOS) is now followed in the development of near infrared (NIR) spectroscopic methods for the pharmaceutical industry. TOS has been the guiding light for a two-step approach for spectroscopic composite sampling available for the development of real-time analytical methods for particulate-based industrial processes. The two-step spectroscopic sample composite has been used in the development of process analytical technology (PAT), an important regulatory initiative to improve the quality of pharmaceutical products. The two-step sample composite approach overcomes the low sample volume analysed by PAT methods; one of the key limitations to PAT implementation in the industrial production of particulate-based materials.PAT methods need to be validated demonstrating their accuracy, precision, specificity and robustness. TOS provides a deeper understanding of these validation studies which involve discrete particulate material. The validation of PAT methods is now being performed considering both sampling and analytical errors, while practically all previous method validations only addressed the total analytical error (TAE) of these methods. This has been a crucial impediment for the field of chemometrics as well.PAT is a key element of continuous manufacturing (CM) processes, which are considered an emerging technology capable of increasing the flexibility, agility and robustness of pharmaceutical processes while reducing their costs. The outflow of the continuous process is a 1D lot, and variographic analysis has been shown to discern process variation from sampling and analytical errors in pharmaceutical CM processes. Thus, variographic analysis is a process improvement tool with significant potential for improving CM processes. The possibilities for improving pharmaceutical manufacturing are enormous.CITATION:Romañach, R J, 2017. Theory of Sampling – from missing link to key enabler for process analytical technology, in Proceedings Eighth World Conference on Sampling and Blending , pp 63–68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By B W. Atkinson, J Docherty

An Australian Working Group has been compiling a guide for operators to use in order to improve the efficacy of their routine and non-routine sampling tasks within their coal preparation process. The guide focuses on unit operations within the process, and not conveyor belts or transfer stations that are adequately covered by the existing Standard ISO 13909.Representative sampling of unit operations is generally an after-thought following plant construction, whether that be a result of oversight, or more commonly, capital cost minimisation during initial construction. Minimising capital cost by avoiding adequate sampling systems is generally a poor decision, since the result is a process that cannot be adequately measured, meaning that it cannot be adequately managed and optimised.The use of the term ‘guide’ rather than ‘standard’ is intentional. Practical means of sampling unit operations within existing plants generally relies on a compromise between sample representativity (minimisation of bias) and sampling feasibility. The guide does not endorse poor sampling practice, but instead offers practical guidance to overcome, to the extent reasonably possible, real-life limitations.When it comes to sampling any particular process, it is almost always necessary to make a professional judgement as to whether or not the proposed samples are likely to be sufficiently representative such that the sampling will be worthwhile. Such judgement needs to be exercised by personnel who understand the principles of sampling, as they apply to the stream being sampled. There are many circumstances where available methods for sampling of a particular stream will be meaningless, and in such circumstances analytical data from that sampling will only serve to propagate poor decision-making.This paper outlines the approach for the guide, the areas it covers and the approaches adopted for different types of unit operations and associated equipment configurations.CITATION:Atkinson, B W and Docherty, J, 2017. A practical guide to sampling in coal preparation plants, in Proceedings Eighth World Conference on Sampling and Blending , pp 241–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By R C. A Minnitt

The two methods for calibrating the parameters K and (alpha) for use in Gy’s equation for the fundamental sampling error (FSE), the duplicate sampling analysis (DSA) and the segregation fractionalised analysis (SFA) are described in detail. A case study using identical broken reef material from a Witwatersrand-type orebody is calibrated using the DSA and SFA methods and the results are compared. Classically, the form of Gy’s equation for the FSE raises the nominal size of fragments given by dN to a power of 3. Gy’s formula is a theoretical formula applicable in the case when fragments are randomly collected one by one, which is obviously never the case. This is because the fragment shape factor (f) and the granulometric factor (g) were introduced to take care of this anomaly. More recent formulae, such as those suggested by François-Bongarçon and Lyman, are empirically based formula. A later modification of Gy’s formula raises dN to the power ? (alpha), the latter term being calibrated with the coefficient K in the DSA and SFA methods. The preferred value of ? (alpha) for low-grade gold ores used by sampling practitioners in the mining industry is 1.5. A review of calibration experiments for low-grade gold ores using the DSA and SFA methods has produced values of K that vary between 70 and 170 and values of alpha in the range 0.97 to 1.30. The average value for alpha is found to be 1, rather than 3 as originally proposed in the classic form of Gy’s equation or the industry preference for 1.5. It is suggested that for low-grade gold bearing ores, the equation for the FSE should raise dN to a power of 1. Such an equation for the variance of the combined FSE plus the grouping and segregation error, now referred to as the short-term component of the quality fluctuation error (QFE1), greatly simplifies the characterisation of gold ores, which now only requires the calibration of K for a given mass and established fragment size. The implications for the heterogeneity test from the generalised equation are that provided the fragments have been screened to within a narrow size range, any particular size will return a value for K that is acceptable for use in the sampling nomogram.CITATION:Minnitt, R C A, 2017. A generalised form of Gy’s equation for gold ores – empirical evidence, in Proceedings Eighth World Conference on Sampling and Blending , pp 331–350 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By G J. Lyman

Sampling of grain for mycotoxins is challenging in that some mycotoxins, such as Ochratoxin A (OTA), have very low permitted levels and the kernels carrying the mycotoxin may be highly localised within the bulk of the grain as ‘hot spots’. Sampling for genetically modified organisms (GMOs) can be fraught with similar problems, especially if the contamination is adventitious and random. Incremental sampling under these circumstances can be shown to lead to a high variance in the sampling result.A new design of sampler for grain and other free-flowing particulates has been developed that is effective in practically eliminating the sampling variance due to distributional heterogeneity (DH).This paper introduces the design and argues that the sampler should be free of sampling variance due to DH.CITATION:Lyman, G J, 2017. A new sampler for grain and other free-flowing particulates, in Proceedings Eighth World Conference on Sampling and Blending , pp 277–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By P Minkkinen

"Pierre Gy showed in his early works that the results in estimating the variance of the mean value of continuous lots depends on sampling mode (random, stratified or systematic), except in the theoretical case that the measurand is randomly distributed in the lot. The experimental variance estimate calculated from samples taken from the lot is independent of sampling mode but depends on sample size and the type of the lot heterogeneity. Variography can be used to estimate the variance of the lot mean for different sampling modes.Gy also defined weighting error, which is made if a simple average is calculated from the assays of samples taken from a continuous object (eg from a process stream) where the flow rate varies with time and is correlated with the concentration of the analyte in the stream.The effect on sampling uncertainty of the three sampling modes and their interaction with the following factors in estimating the uncertainty of the mean concentration is studied using simulated lots, and lots having heterogeneity patterns similar to those of real data sets, including the effect of: the type of heterogeneity (random, grading and clustered heterogeneity patterns) increment size and number employing composite sampling weighting error. CITATION:Minkkinen, P, 2017. Dependence of the variance of lot average on the sampling mode and heterogeneity type of the lot, in Proceedings Eighth World Conference on Sampling and Blending, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By A C. Chieregati, A Heberle, F L. S P Villanova

Since the publications of Gy’s initial work, many authors have discussed the approaches to estimate the variance of the fundamental sampling error (FSE). Experimental tests suggested by Pitard and François-Bongarçon determine the sampling parameters K and a to calibrate Gy’s formula. The heterogeneity test and the sample tree method are well known and broadly used for many commodities. However, prior to the analysis, the collection of a representative sample is an intriguingly difficult task. The composite for the heterogeneity tests often consists of run-?of-?mine material or processed ore on a conveyor belt. In most cases the final sample does not have enough mass, mixes different geological units, represents a rare blend and does not characterise the deposit. In order to obtain a reliable composite for trace elements and low-grade ores, sampling practitioners suggest at least half a ton of material.To prevent the common representative pitfalls in the FSE, this case study focuses on a single gold-?bearing geological unit collected in situ. With this unit being structured by the mine geologists, but with the interaction between engineers and chemists, it was possible to validate the reconciliation suggested by Pitard (2015). The heterogeneity test and the sample tree method were performed using 500 kg of a smoky quartz from a single geological domain and the results were compared to Gy’s formula. The logging practice by the geologists was modified, emphasising the definition of the size of the gold nugget or its cluster, number of grains and association. Finally, a mineralogical study was conducted on the geological unit to define the liberation factor. All the information is compiled in this paper, showing the need to fully understand the mineralisation to correctly define representative samples and proper analytical techniques.CITATION:Villanova, F L S P, Heberle, A and Chieregati, A C, 2017. Heterogeneity tests and core logging – a final reconciliation, in Proceedings Eighth World Conference on Sampling and Blending , pp 107–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By M Singh, R C. Steinhaus, J J. Rust

Metallurgical process control systems in mineral plants often employ state-of-the-art monitoring analysers in an attempt to optimise plant operations and enhance mineral recoveries. These systems are unfortunately invariably fed by simplistic ‘sampling’ designs consisting of various in-stream methods or pressurised probes. These are unfortunate compromises and provide a false picture of what a mineral flotation or other process can achieve. The situation is further aggravated by some manufacturers using misleading marketing to suggest discrete cross-stream methods for metallurgical accounting and unreliable continuous in-stream off-takes for control sampling and that they are of synonymous integrity.Reliable, absolute or representative samples are often absent in many modern day concentrator plants, due to compromises around sample taking, particularly in terms of delineation and extraction errors and thus leading to sample bias. For more reliable information from online analysers we need a continuous, but much more reliable sample taken, than is current practice.Online analysers require a fully proportional and continuous supply of sample for effective process control, otherwise maximised or benchmark recoveries will be nothing but a pipe dream. Large discrete cross-stream samples from mechanically less reliable equipment cannot be used as feed to online analysers, as it will negatively impact real-time feedback and efficient process control.It is possible to build correct sampling systems that could do both process controls online and metallurgical accounting at the same time. Multotec Process Equipment (Pty) Limited, in close association with experienced sampling consultant Francis Pitard, have jointly patented a concept to achieve this and which is embodied in the design of the unique Rotating Cone® Sampler (International Patent Application No. PCT/IB2016/057464). This versatile unit for dry and wet applications has high division ratios via two-step sampling and division.A prototype was built and tested to validate the design and levels of precision achievable when employing the unit to split dry mineral fines or even certain foodstuffs.CITATION:Steinhaus, R C, Rust, J J and Singh, M, 2017. Does process control sampling always have to be a compromise?, in Proceedings Eighth World Conference on Sampling and Blending , pp 197–202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By N H. Jansen, H L. Bridgwater

Field portable X-ray fluorescence (XRF) and near infrared (NIR) instruments are proven technologies in the minerals industry. The in-field results of these instruments can add value early in the project life, leading to cost-effective decision-making compared to their equivalent laboratory based techniques. However, in order to add value to a project, it is crucial that the instruments are employed correctly.Orientation studies should be carried out prior to initiating a sampling program to achieve the highest level of quality assurance and control for the results. Hence, an appropriate sampling workflow begins with considering what outcomes are required, including level of precision, accuracy, reliability for elements and minerals of interest, and sampling errors. The workflows proposed include soil sampling and reverse circulation and diamond drilling sampling techniques, and laboratory based techniques. They are practical and flexible workflows using available portable XRF and NIR technologies that can be applied to current sampling and drilling methods.The combined technologies have the ability to create large, integrated geochemical and mineralogical data sets that can provide cost savings for every stage of the mining chain from exploration to prefeasibility, mineral processing and environmental remediation.CITATION:Jansen, N H and Bridgwater, H L, 2017. Proposed workflows for portable X-ray fluorescence and near infrared instruments for soil and drill hole sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 219–228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017